Torque vs Horsepower: Auto Racing Power Showdown

[cesiumfrog]

If you had no forces resisting movement (impossible), and some kind of hypothetical engine which does not rely on the laws of physics to make it go (impossible), then the car would keep accelerating until relativistic effects take their course. It's meaningless to even consider such a scenario. [emphasis added]

it doesn't consider the mass of the drivetrain and leaving that mass off is just as big of a sin as leaving the mass of the car out. An "ideal situation" never leaves out such an important factor.

Physicists are normally reductionists. That means applying a strategy of "divide and conquer" in order to understand complex systems.

It isn't wrong, meaningless, nor sinful, to ask how a vehicle would behave without friction (and/or with an "ideal" transmission). To the contrary, a good first step in understanding any phenomena is to isolate the cause.

Perhaps you could imagine a biologist taking a different approach: group cars according to high and low top speed, then survey whether the faster ones use different fuels, lighter engines, more horsepower, or brighter paint. This process will indeed uncover the parameters that should be optimised to achieve a (local) maximum in performance, but it doesn't build an understanding of why, whereas the typical physicist's approach aims even to deducing parameterisation of the global maximum.

 

[fedorfan]

Thanks yall.

 

[5.0stang]

My point is that if you go to the track and ask the successful drag racers how they're tuning their cars, you will find that they want their torque (powerband) optimized for the higher rpms and they want the powerband wide enough to cover their shift points. They launch pretty hot and flog 'em down the stretch and they want to continue to accelerate strongly in each gear, so the torque has to be available over a range of RPMs that exceeds the RPM drop caused by shifting to each higher gear. Peak horsepower is a "nice to know" number, but to continuously accelerate, you need to deliver that power effectively over a usable range of RPMs. That's the importance of the torque vs RPM curve on a dynamometer plot. If the absolute value of your car's torque is relatively high and the high portion of the curve is wide enough to cover your shift points (gearbox dependent), you will outperform a competitor with higher absolute torque values if his curve does not adequately span the RPM differential at his shift points. His acceleration will not be consistent because his torque curve is narrow and peaky and since acceleration adds cumulatively to velocity, your car, with a slightly lower but broader torque vs RPM curve will win out.

I agree, I never disputed that. I wasn't talking about "peak horsepower." That is just bragging rights on the dyno. A broad horsepower/torque band is what is needed.

I was saying that the fastest street cars in the worlds all have more horsepower output than their highest torque value. Nothing more.

 

[russ_watters]

It's my patent response to the question in the OP, and of course it has meaning.

Not really - if you use the SI system, they cross at a 9.5 rpm. Frankly, that has more meaning since there is a logical basis for the units, whereas a horsepower is just an arbitrary number. 1 watt = 1n-m/sec, while 1hp = 550 ft-lb/sec.

If I made up another unit of power, (lets call it the "Watter" ), and defined it as 100 ft-lb/sec, then the graphs would cross at 52.5 rpm.

 

[russ_watters]

Physicists are normally reductionists. That means applying a strategy of "divide and conquer" in order to understand complex systems.

Certainly true. All I am saying is that there is a limit to how far you can reduce something and keep it useful. Whether or not it makes sense to eliminate certain factors depends on the context and is somewhat a matter of opinion.

 

[polar]

Not really - if you use the SI system, they cross at a 9.5 rpm. Frankly, that has more meaning since there is a logical basis for the units, whereas a horsepower is just an arbitrary number. 1 watt = 1n-m/sec, while 1hp = 550 ft-lb/sec.

If I made up another unit of power, (lets call it the "Watter" ), and defined it as 100 ft-lb/sec, then the graphs would cross at 52.5 rpm.

on edit> I do understand that for this discussion power is a funtion of the three properties; force (torque), distance (revolutions), and time (minutes), and that the dimensions of the units are not all that important.

I also understand that using ft-lbs for units just breeds more confusion, since the term has two different accepted meanings for different properties, one is a unit of work (a scalar quantity) and the other is a moment of a force (a vector quantity).

I still think the observation is a valid one, especially when discussing the differences between engines. By making an observation of something that is the same about all engines, a better understanding can be had of what effects our choice of properties to discuss has on our perceptions of what those properties mean when put into action. Or something like that. In this case, the fact that the graphs cross at the same point, no matter the engine, is the important thing.

I used to keep a small stack of popular magazines because they all had hp/torque graphs in them that did not cross at 5252 rpm (and yes, the torque was plotted in ft-lbs). The only logical explanation was that after multiple dyno runs they kept the best hp and the best torque and plotted them together on the same graph.

 

[polar]

I was saying that the fastest street cars in the worlds all have more horsepower output than their highest torque value. Nothing more.

I don't think so. Back in the 50's, it seems like there were a few street cars that weighed in the 1200 pound range with around 200 hp. I think some were long stroke motors with massive torque (taxes in Britian were based on bore). They are still really fast cars.

With modern materials like carbon fiber, what you are saying is probably true again today, but it wasn't always this way, maybe up until just a very few years ago.

 

[K.J.Healey]

Just wondering if i can pop in and ask a simple question then.
So HP and Torque are proportional (right? P(w)=wT(w)) as stated earlier, there would be no non-theoretical factor to limit us from making an imaginary engine with say, constant torque and HP. So its level across the RPM range.
With said engine, let's make it so the engine has 100 units of HP and 100 units of torque equally across its 0 to 10,000RPM range. You take two of these engines and modify them and put them in identical cars. One engine you double the HP across the board to 200, and the other you double the torque across the board.
Which would hit 500 meters first?
Which would hit 100 km/hr first?
I assume there would be a difference in their acceleration pattern, say the more torque-pumped engine accelerating faster at first, but then the HP one catching up. Is it possible to derive a function to predict when they would hit the same speed again after start, and when one would overtake the other? Assuming a very very theoretical engine once again. I figure gears wouldn't even matter if we force the values of T and HP to be constant.

 

[joema]

...an imaginary engine with say, constant torque and HP. So its level across the RPM range...the engine has 100 units of HP and 100 units of torque equally across its 0 to 10,000RPM range...One engine you double the HP across the board to 200, and the other you double the torque across the board...Which would hit 500 meters first?...

In theory you can approximate this with a continuously variable transmission. That effectively produces an engine which stays at peak power (or peak torque) over the entire acceleration run. In that scenario whatever engine has the highest peak horsepower (translated to constant hp by the CVT) will accelerate faster, regardless of torque.

Another way to approximate the "flat horsepower" test is using an electric motor. However electric motors typically have very high torque. Don't know what various configurations are available to achieve your stated scenario.

 

[5.0stang]

I don't think so. Back in the 50's, it seems like there were a few street cars that weighed in the 1200 pound range with around 200 hp. I think some were long stroke motors with massive torque (taxes in Britian were based on bore). They are still really fast cars.

With modern materials like carbon fiber, what you are saying is probably true again today, but it wasn't always this way, maybe up until just a very few years ago.

1200lbs?...wow! Got any examples? Do you remember the make and model? How was the torque output compared to the horsepower output?

I think in a lot of cases, dyno graphs would be nice to look at...we can look visually and see where the "racing rpm" is and see which is higher on average, hp or tq. Some dyno graphs of the fastest cars, enzo, mclaren f1, diablo, etc would be nice to look at.

 

[brewnog]

Just wondering if i can pop in and ask a simple question then.
So HP and Torque are proportional (right? P(w)=wT(w)) as stated earlier, there would be no non-theoretical factor to limit us from making an imaginary engine with say, constant torque and HP. So its level across the RPM range.
With said engine, let's make it so the engine has 100 units of HP and 100 units of torque equally across its 0 to 10,000RPM range.

You can't, because by definition torque and power are proportionally related by speed. The power can't be 100 units across the speed range unless the torque decreases linearly as speed increases. So if, at 100rpm and 100 torque it produces 100 x power, then at 10,000rpm, to produce 100 torque again you require 1/100 the torque you did at 100rpm.

And horsepower is not an arbitrary unit, it's defined.

 

[russ_watters]

And horsepower is not an arbitrary unit, it's defined.

Where does the definition come from?

To help sell his steam engines, Watt needed a way of rating their capabilities. The engines were replacing horses, the usual source of industrial power of the day. The typical horse, attached to a mill that grinded corn or cut wood, walked a 24 foot diameter (about 75.4 feet circumference) circle. Watt calculated that the horse pulled with a force of 180 pounds, although how he came up with the figure is not known. Watt observed that a horse typically made 144 trips around the circle in an hour, or about 2.4 per minute. This meant that the horse traveled at a speed of 180.96 feet per minute. Watt rounded off the speed to 181 feet per minute and multiplied that by the 180 pounds of force the horse pulled (181 x 180) and came up with 32,580 ft.-lbs./minute. That was rounded off to 33,000 ft.-lbs./minute, the figure we use today.

There are at least three levels of arbitrary-ness in there. First is why don't we use oxpower or mulepower, second is where the 180lb of force came from, and 3rd is the rounding.

http://www.web-cars.com/math/horsepower.html

 

[brewnog]

Where does the definition come from?
There are at least three levels of arbitrary-ness in there. First is why don't we use oxpower or mulepower, second is where the 180lb of force came from, and 3rd is the rounding.

http://www.web-cars.com/math/horsepower.html

Sorry, I just meant that when Healey01 said:

With said engine, let's make it so the engine has 100 units of HP and 100 units of torque equally...

that "100 units of HP" actually means "100 horsepower" rather than "100 arbitrary units".

 

[polar]

1200lbs?...wow! Got any examples? Do you remember the make and model? How was the torque output compared to the horsepower output?

I think in a lot of cases, dyno graphs would be nice to look at...we can look visually and see where the "racing rpm" is and see which is higher on average, hp or tq. Some dyno graphs of the fastest cars, enzo, mclaren f1, diablo, etc would be nice to look at.

Lotus Seven for one, but it's not all that unique for the time period. A few years back, some magazine tried to match up a new Lamborghini with some of these period classics and it was pathetic. Except on very, very long straightaways, these little tiny cars tore things up. (Woudn't want to hit a pebble in one at top speed, though.)

snip>

Low speed acceleration

Nearly all Sevens, due to their extremely light weight (around 500 kg) have excellent acceleration, especially up to 70 mph, depending on power. For their time, the original late 1950s Sevens could beat most contemporary saloon cars—and by the early 1960s, with improved Ford-Cosworth engines could take on most high performance sports cars with 0–60 mph time in the low 7 seconds. More recent acceleration times (for top level models) are world beating for production cars with 0–60 mph below 3.5 seconds. The high power-to-weight ratio is excellent with almost any engine.

snip>

Weight

Early Lotus Sevens weighed around 1100 lb (500 kg). Although the weight crept upward as production progressed, it remained remarkably low for a production car of over a litre displacement. Superlight production models weigh well under this and the latest high performance model reports a stunning, world class power / weight ratio in the region of 600 hp (447 kW) per metric ton or 3.7 lb per hp.

snip>

http://en.wikipedia.org/wiki/Lotus_Seven

Many different engines were used in a lot of different versions (and makes and models) of this class of cars, and most of them were not all that high-revving. The Ford Kent engine that came about in the 60’s was (I believe) sort of the first successful over-square (short-stroke, high revving) engine for this class of car. The way I understand it, the early Cosworths were under-sqare, with large torque - much different from the later Ford Cosworth engines that we are more familiar with. Sorry I don’t have dyno runs to back me up on any of this, but I think it’s generally accurate.

 

[brewnog]

I've got a Seven.

While the power of the current ones isn't high by supercar standards (260bhp is currently easily available), they do indeed only weigh around 550kg, so the power/weight ratio can be pretty exciting and they'll accelerate to 60 in 3 seconds. That's pretty good for something which costs about the same as a family saloon.

 

[polar]

I've got a Seven.

While the power of the current ones isn't high by supercar standards (260bhp is currently easily available), they do indeed only weigh around 550kg, so the power/weight ratio can be pretty exciting and they'll accelerate to 60 in 3 seconds. That's pretty good for something which costs about the same as a family saloon.

I hate you.

 

[5.0stang]

Lol...

Yeah those times are right on par with the top sports cars of today from 0-60mph.

Power to weight works wonders!

 

[poiney]

That's certainly true. It comes up so much in some other forums I frequent that I've thought about writing up a canned response. But I haven't done that yet, so here's another try:

People often confuse power and torque because car enthusiasts tend to (unknowingly) use these words for different concepts. This is a physics site, so I'm going to go ahead and use the definitions from physics.

The full-throttle behavior of an engine can be approximately modeled as a device which has some function $\tau(\omega)$ associated with it. This fixes the torque it can produce as a function of engine speed (rpm). This function is not at all constant, although engineers often strive to make it as flat as possible.

Regardless, given the torque function, there is an associated power $P(\omega) = \omega \tau(\omega)$. So if the torque is known at all speeds, the power is known at all speeds (and vice versa). You can't have one without the other.

Despite this, it is common practice for engines to be advertised only in terms of their peak torque and peak power. The engine speeds where those conditions may be found are also usually given. The peak power is very important for reasons I'll get to later, but the peak torque is essentially useless all by itself. The reason is that the gearbox can multiply the torque to (essentially) any amount whatsoever at an appropriate speed. But an ideal gearbox cannot change the power.

Staying with the ideal case, the maximum forward force that a car can produce is entirely determined by the power its engine is producing and the car's overall speed. So fixing speed, maximum acceleration is always reached by maximizing the engine's power output. It is the job of the transmission (and driver) to use the gearbox to keep the revs as close to the engine's power peak as possible if full acceleration is desired.

Modern transmissions have many closely-spaced ratios, so except at very low speeds (at the bottom of 1st gear), an engine may be kept close to its power peak for as long as desired. That means that a well-designed car that is driven well may produce a force $F \sim P_{\rm{peak}}/v$. This depends only on the peak power (and velocity), and explains why the power-to-weight ratio is such a good predictor of acceleration performance.

Having said that, the torque peak is not completely irrelevant. Its position relative to the power peak is usually a good indicator of the size of the car's "powerband." Essentially, how high do you have to rev it in a given gear before the engine really gets going? Having a wide powerband is extremely important in everyday (or moderately aggressive) driving where you're not going to redline in every gear. It makes the car feel much more powerful even if the maximum performance is the same. Of course, a wide powerband is also useful if your have a poor transmission or don't want to shift as much.

Russ, differences in drivetrain inertia between reasonable designs are not usually not a huge effect. They're certainly significant, but I don't think I'd include them given the approximations already inherent in this sort of discussion.

This is a good/correct explanation. I think that the problem with this discussion is that different folks makes different assumptions w/o being explicit in their assumptions. People get confused by trying to solve this with torque, which is difficult. If we assume that Horsepower is constant, it's much easier to think of simply increasing kinetic energy the most rapidly, which of course necessarily provides the highest average acceleration as well.

 

[rcgldr]

As mentioned, for an engine, what counts is peak horsepower and the shape of the torque versus rpm curve (the effective width of the powerband). Knowing the peak torque without knowing the rpm peak torque occurs at, is not enough information to determine peformance. However, knowing the peak power without knowing the torque is enough information to know peak peformance.

Some formulas:

Using the english system, horsepower is force (lbs) times speed (mph) divided by 375:

Let P = power, F= force, S = speed
1 hp = 550 lb x ft / sec
P/hp = force (lb) x speed (mile/hour) x (5280 ft/mile) (hour / 3600 sec) (hp /(550 ft lb / sec))
P/hp = (F x S) / 375

Power versus torque x rpm in english units:

P/hp = torque (lb ft) x (rev/min) (2 x pi / rev) (min / 60 sec) (hp / (550 ft lb / sec))
P/hp = (torque x rpm) / 5252.113122...

Power versus torque x rpm in metric units:

1 horsepower = 745.69987158227022 watts = .745... kw (kilo watts)
1 foot = .3048 meter
1 pound = 4.44822 Newtons
P/kw = torque x rpm / 9549.2966...

Other tidbits:

The drivetrain is an important factor since it consumes power. The time it takes to shift is also important, since no power is transferred during a shift. Shift times with a manual transmission can take 1/2 second or more. A typical automatic shifts about the same, but power losses through the fluid clutch add to the overall power consumption. I don't know how efficient CVT type transmisions are. A computerized no lift sequential shifter, such as an XTRAC, can complete a shift in 30ms to 50ms, depending on rpm drop, and are used for race cars where this type of transmission isn't banned.

A typical Formula 1 race car uses a 7 speed, no lift sequential shifter. High end drag cars make so much power that they typically just use a single forward speed transmission. The clutch does all the slipping to keep the tires near their limits of traction, consuming the excess power from the engine. Engine rpms are virtually constant until near the end of a run.

The final component is the tires, getting the power to the pavement. Stickier tires will allow for more acceleration.

low speeds in first gear

At low speeds in first gear, a slipping clutch or spinning tires allow the engine rpms to be high enough to be in the power band. Depending which has better effective dynamic traction, it may be better to spin the tires rather than slip the clutch when launching a car. A lot of cars have clutches designed to limit dynamic traction to avoid drivetrain damage, in which case it's better to launch with spinning tires.

A 2006/2007 Corvette Z06 has a electronic torque limiter to protect the drivetrain, so it has a sticky clutch. It also has traction control (reduces engine power) that allows some slippage, and stability control (individual computerized wheel braking) to keep the car stable. Even though first gear redlines at 61mph, the car is traction limited (the tires spin) unless the tires are fairly warm(or the owner switches to a very sticky tire).

 

[rcgldr]

A bit off topic, but since I used to own a Caterham SV with a souped up Ford Duratec 2.3 liter motor, I thought I'd respond.

I've got a Seven. While the power of the current ones isn't high by supercar standards (260bhp is currently easily available), they do indeed only weigh around 550kg, so the power/weight ratio can be pretty exciting and they'll accelerate to 60 in 3 seconds. That's pretty good for something which costs about the same as a family saloon.

Caterham now owns the license for making Lotus 7 replicas and well as the enhanced versions. Other companies also make Lotus 7 replicas.

The ones that can accelerate 0 to 60mph in the low 3 second range aren't cheap, about $66,000 or so (USA) for the CSR 260 (which in the USA is 250hp because of lower octane gas). The Caterhmas are very light, but the coefficient of drag is around .7, (double that of a Corvette Z06) so top speed is limited to 155mph on the CSR 260.

Pics of the oversized go-kart (Caterham) I used to own:

caterham pics htm

Official web site:

http://www.caterham.co.uk/assets/html/showroom.html

 

[brewnog]

Ahhhh, cycle wings! A man after my own cause.

 

[IMP]

We had a version of this discussion over on the EVO web site. The question was whether or not replacing a flywheel with a lighter-weight unit added horsepower or not. After much debate it was determined that a light-weight flywheel DOES add horsepower, but does NOT add torque. Horsepower is a measurement of torque VS time.
Removing rotating weight from the flywheel decreass the time required to do the same amount of work: more horsepower. Or to look at it another way, you can do more work in the same amount of time.

 

[rcgldr]

The question was whether or not replacing a flywheel with a lighter-weight unit added horsepower or not.

The affect on acceleraton is extremely small because the total total momentum of the car (plus angular momentum of the drivetrain, clutch, and engine), is much more significant.

The main purpose of a lighter flywheel is for faster rpm changes during shifts, to allow for reduced shift times. It also reduces the stress on the drivetrain during fast shifts.

On the other hand, a heavier flywheel can prevent overrev damage from downshifting at too high a speed, by skidding the driven tires, but this is done for street cars, not race cars.

 

[Stingray]

The affect on acceleraton is extremely small because the total total momentum of the car (plus angular momentum of the drivetrain, clutch, and engine), is much more significant.

That's not true. The flywheel has a significant effect on acceleration in the lower gears. But it's not accurate to say that it takes away power per se (or torque, which is inseparable). It actually acts like an effective mass which scales as the square of the overall gear ratio. In 1st gear, it will make a typical car feel 2-300 lb heavier under acceleration.

 

[IMP]

That's not true. The flywheel has a significant effect on acceleration in the lower gears. But it's not accurate to say that it takes away power per se (or torque, which is inseparable). It actually acts like an effective mass which scales as the square of the overall gear ratio. In 1st gear, it will make a typical car feel 2-300 lb heavier under acceleration.

Actually, power and torque are seperate. Torque can be static. Take an electric motor and weld the output shaft to the casing and then turn the motor on. It will sit there and make its full start-up torque for as long as it is plugged in, but no work is being done (you just have a big heater). If you allow the torque to be used: The amount of work it will do in a given amount of time is horsepower.
The effect a light-weight flywheel has on a car is very noticable in the lower gears for sure. It does make launching the car more difficult though, because you don't have as much stored mass that a heavy flywheel has. A heavy flywheel really helps get the car moving from a dead stop.

 

[Stingray]

Actually, power and torque are seperate. Torque can be static. Take an electric motor and weld the output shaft to the casing and then turn the motor on. It will sit there and make its full start-up torque for as long as it is plugged in, but no work is being done (you just have a big heater). If you allow the torque to be used: The amount of work it will do in a given amount of time is horsepower.

That disabled motor will not be doing any mechanical work. Its power output is therefore zero. Of course it does require electrical power to run, but that all goes into heat. Internal combustion engines are always rotating when they're being useful, and their power output is equal to the torque multiplied by the (crankshaft's) angular velocity. Since your welded motor has no angular velocity, P = 0. At any nonzero rpm, dropping the power output by a certain percentage drops the torque by that same amount.

In a car, the effect of the flywheel depends on how quickly you try to spin it up. If you're not slipping the clutch, that's entirely determined by the car's acceleration together with the gear ratio between the wheels and flywheel. It follows that in an actual car, rotating driveline parts act like additional effective masses in terms of longitudinal acceleration. Those masses are dependent on the gear ratio. If you tried to say that the power changed instead, you'd find an effect which varied with gear ratio, rpm, and external load (e.g. drag). That's hardly a natural thing to do.

 

[rcgldr]

Flywheel versus acceleration

Is this is reference to race cars or to street cars? Race cars only launch at the start and out of the pits, so even first gear is pretty tall. Generally race cars are traction limited in 1st gear, so flywheel weight won't affect acceleration.

As I stated previously, the main advantage of a lighter flywheel is quicker shifts and less stress on the drive train. In order for an XTRAC like sequential shifter to shift in 30ms to 50ms (1/33 to 1/20 of a second), the flywheel has to be very light.

Some high end 4 cylinder motorcycle engines just rely on the clutch and counter-balancer for flywheel effect. Racing bikes remove the counter balancer.

 

[rbj]

Enzo Ferrari was once quoted as saying "Horsepower sells cars, torque wins races". Obviously Mr. Ferrari believed that torque was most important of the two provided that both were present in sufficient amounts. With lots of turns, acceleration, and braking, torque wins hands down IF there is sufficient horsepower. Without the horsepower, diesel trucks would win auto races. Without torque, jet-powered cars would win all the races. By the way, I believe a jet powered vehicle holds the land speed record... of course it just went straight and probably didn't handle well in the turns!

someone (maybe you) posted this before and i still don't get what the thing is. the issue with torque is gear ratio. providing you have sufficient HP in your engine, getting the torque you need to maximize accelleration is a matter of having the necessary gear ratio in the tranny. but getting the sufficient HP is a more fundamental problem of having an engine of sufficient capacity to convert chemical energy to mechanical energy at a sufficient rate. the latter affects the mass of the vehicle (which also affects acceleration) whereas the former does not to anywhere close to the same degree.

so i would say to Ferrari that, first make sure you have sufficient power output (which is the product of crackshaft angular speed and torque) for the total mass of vehicle to accomplish the performance goal needed, and then the rest is the design of the necessary gear ratios so that this power is transformed to the torque and speed values that suffice for the race.

 

[brewnog]

so i would say to Ferrari that, first make sure you have sufficient power output (which is the product of crackshaft angular speed and torque) for the total mass of vehicle to accomplish the performance goal needed, and then the rest is the design of the necessary gear ratios so that this power is transformed to the torque and speed values that suffice for the race.

Except that it's not nearly that simple, because the torque/power characteristics of an engine are not linear with engine speed.

 

[Stingray]

Is this is reference to race cars or to street cars? Race cars only launch at the start and out of the pits, so even first gear is pretty tall. Generally race cars are traction limited in 1st gear, so flywheel weight won't affect acceleration.

I was talking about street cars when I gave the 2-300 lb estimate.

In race cars, I agree that small flywheels are mainly to shift quickly. But their effective mass effect is also important. Although 1st gear is usually designed such that redline occurs at a relatively high speed, those redlines are usually much higher than in street cars. The overall gear ratio is therefore pretty big. The (static) weight of a race also tends to be small, and every little bit counts.

Just for fun, I've calculated what would happen if you gave an F1 car a flywheel from a roadgoing V8. Say that a redline of 20,000 rpm occurs at 70 mph, and that the rear tires are 22 inches in diameter. Then a 30 lb flywheel 11" in diameter would add an effective mass of about about 1,900 lb! It's obvious that nobody would ever try to race like that, but I think it shows that these things are still important.

 

[rcgldr]

I underated the affect of flywheel weight versus acceleration in low gears, since I was thinking race cars, not street cars. Street cars use heavier flywheels to reduce vibration and for easier launches with a manual transmission, and a better idle. There is a peformance advantage in the lower gears with a lighter flywheel beyond faster shift times.

Some typical flywheel weights for street cars, stock and lightened.

Mitsubishi Starion 2.6 Turbo...35 lbs. stock / 21 lbs. lightenend
Datsun Z car 225mm...25 lbs. stock / 16 lbs. lightenend
Datsun Z car 240mm...28 lbs. stock / 18 lbs. lightenend
BMW 2002 215mm...18 lbs. stock / 11 lbs. lightenend
BMW 2002 228mm...24 lbs. stock / 16 lbs. lightenend
Datsun 240SX KA24DE 24-25 lbs. stock / 16-17 lbs lightened

The engines in these car only rev to 6500rpm or less, and the cars weigh 3000lbs or more. The cars probably redline at around 35mph in first gear.

I was previously thinking peformances cars, like a C6 Corvette Z06, redlines at 7100rpm at 61mph in 1st gear, or a motorcycle like a Hayabusa, which redlines at 11,000 rpm at 81mph in 1st gear. A F1 race car redlines at 18,000 to 20,000 rpm at around 100mph in 1st gear (note that 7th is geared around 185mph to 225mph, depending on wing setting for the track, a very close ratio tranny).

A F1 race engine has a tiny flywheel and can change rpms very quickly, as in the later part of this video:

f1 engine warm up

 

[IMP]

Maybe we are getting just a bit off topic here but: If you want to hear a Formula One engine sing, check this out:

 

[aliaze1]

Ive got a question, which is more powerful and better to have in auto racing, torque or horsepower? I've gotten mixed answers and wanted to ask some people who know their stuff.

you need a balance of the two, each has its purposes, i don't know the details exactly.

but if u notice, some of the amazing sports cars like the Subaru WRX STi have large numbers of both, in the case of the STi, 300hp and around 300ft-lb torque (i don't remember exactly)

 

[rcgldr]

The faster the shift time, and the more gears, the less important it is to have a wide powerband (shape of torque curve versus rpm). In Formula 1 racing, times have changed since Ferrari made that statement. Shift times are 50ms or less (electonic sequential no lift shifters, activated by paddles), and the cars use a 7 speed close ratio tranny. My guess is only the top 25% of the rpm range is used in these cars. In the older days of manual shifts and only 5 or 6 gears, the top 40% of the rpm range might have been used.

 

[Stingray]

Just to set the record straight, I'm pretty sure that the Ferrari quote is an urban myth. I've usually seen the statement associated with Carroll Shelby, but I doubt he said it either.

Also, F1 cars have had very close ratio gears for a long time. A typical racer from the 60's would rarely drop its revs more than 15% on an upshift (except for the 1->2 shift where you were pretty much traction-limited anyway).